"Writes to the WAL are purely sequential and writes to long-term storage are purely sequential."
Is that simply a typo or am I missing something? Shouldn't it be mostly random for long-term storage?
Is that simply a typo or am I missing something? Shouldn't it be mostly random for long-term storage?
In the worst case though, the long-term storage can still have random writes though no (for btrees anyway)? I figure LSM tree writes can always be sequential, even during compaction. But btrees can only do solely sequential writes if the entire tree needs to be rewritten. And you don't want to always do that if only parts of the tree need to be updated?
With all the different layers in modern storage, I think you can get asymptotically close to the sequential rate once you start hitting some of these other multi-block granularities, i.e. around the block size for flash erasure, encryption, redundancy coding, etc. These don't have to be that big, i.e. several megabytes.